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I thought it would be useful to put a light on the dash to indicate when i am on the brakes, to help interpret / learn from in-car video. I have this set of lights from an old sequential shift light. Anyone know how to hook this 7-pin connector to a plunger type swith and make the lights come on sequentially as pressure on the brake increases?
Jim,
I'm afraid that is basically out of the question. You (someone) would have to develop and build a circuit to convert brake pedal travel (or pressure) to a frequency that would activate the shift lights in sequence. Easier and cheaper to build one from scratch using a potentiometer to indicate pedal position.
That said, it is PROBABLY almost as good to know when your foot is on the pedal at all - a simple on/off switch (brake light switch) to activate a single dash light to show when you are 'activating' the brake. Could use a second one to show throttle. (we all KNOW that you should ALWAYS be either ALL IN or ALL OUT of either, right ? :D:D As long as the lights are independent, you would also show left foot braking overlap .. as long as you use LED type indicators and not incandescent.
Showing pedal PRESSURE or throttle POSITION is considerably more complicated and beyond the scope of this reply :D.
Steve, FV80
Steve has a good ide and one I have had a similar version off and just used basic toggle switches and a light on top of the dash in to different colors. For drivers , like me, who left foot brake I encounter a lot of them who rest their foot on the brake pedal w/o knowing it. I pulled mine back and just let the belts hold me tight. I put a switch on the pedal attached to a red light that would light every time the brake pedal moved so the driver was notified how much he was resting on the pedal. Our straight line speeds shot up. For the throttle it only lit the light at full throttle. " Hedid T1 at Mid Ohio flat out !!!..ahh damn light isn't on , no I didn't"
Sure data shows all this but after the session is too late to find out the mistakes you made that are easily correctable. Just a thought.
Anything is possible with a micro controller! If you're set on doing what you asked for, I'd pick up an arduino and a cheap brake pressure sensor (like a Bosch sensor from a BMW, used from eBay!) and go to town. You'll have to figure out what the 7 pins do on the connector (ground and 6 lights? Or maybe some unused pins? Who knows..) and write a little bit of code on the arduino to turn on each light based on the output of the brake sensor.
If you just want to look at it in the video though, I'd use a data logger and something that renders the data over the video like racerender or whatever it's called. The LEDs won't always be Perfectly visible in the video, I don't think..
I have banjo bolts that are wired (2 wires) with a pressure sensor.
All you do is replace a banjo bolt on one of the master cylinders, or any other location that uses one and you have the switch needed.
Guys,
thanks for the ideas. I don't know what an arduino is, so I'd need some more explantion there. I was imagining some type of plunger switch set up as a rheostat /potentiometer [big words I am vaguely aware of but can't define] More pedal travel --> more voltage through the switch--> more lights turn on. I will look into Keith's idea also.Then, I may have a nice, used, sequential shift light kit to sell, cheap!
I don't like the idea of equating pedal travel to line pressure. Pedal travel is certainly not only a function of pedal force. Pedal force is much more closely related to braking torque. Pedal travel depends on too many things (pad wear, brake fluid temperature, etc.) to be a good indicator of brake torque.Quote:
Originally Posted by swiftdrivr
Dave,
Point taken.
Jim,
Get an AIM SmartyCam and you can superimpose the longitudinal g's on the screen as an indicator of effective breaking.
Example of my implementation here: http://youtu.be/3gTQOrzvNog
Sean
I believe what you want is an LM3916 chip, it drives a 10 segment bar graph. Of course you'd have to either amplify or divide the signal from your pressure transducer to match the output to the range of the chip and and connect it to whatever you want to use as a display. I did this once for another project, but no, I am not interested in doing it again. If you can find a bright student somewhere they should be able to do it fairly easily.
Link the ti chip data sheet below.
http://www.ti.com/product/lm3916
BTW we program MoTeC shift lights to be brake pressure indicators under braking. I drive with that, and I find it's a good reminder if I'm not using the middle pedal hard enough...
So I think it's a good idea.
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